BugwoodWiki Article

alligatorweed
Alternanthera philoxeroides (Mart.) Griseb.

Overview

Appearance
Alternanthera philoxeroides is an emergent or rooted floating plant that invades aquatic areas and adjoining uplands throughout the southern portions of the United States. Plants have hollow stems and can grow to 3 ft. (1 m) tall.
Foliage
Opposite, elliptical leaves are thick but non-succulent and are up to 4 in. (10 cm) long.
Flowers
Flowering occurs during the summer with white, clover-like heads in the axils of the leaves.
Fruit
Fruits are very small, and single-seeded.
Ecological Threat
Alternanthera philoxeroides roots in wet soils or shallow water and grows out into waterways. Alternanthera philoxeroides can also grow terrestrially, forming smaller, tougher leaves. The thick mats can displace native vegetation and wildlife habitat, clog waterways, restrict oxygen levels of water, increase sedimentation, interfere with irrigation and prevent drainage. It is native to South America and was first introduced into the United States around 1900 in ballast water.

Resources

Selected Images


1237068
1237068

alligatorweed
Alternanthera philoxeroides
Flower(s)
Robert H. Mohlenbrock
4723003
4723003

alligatorweed
Alternanthera philoxeroides
Flower(s)
Gary Buckingham
5422950
5422950

alligatorweed
Alternanthera philoxeroides
Foliage
Rebekah D. Wallace
1539030
1539030

alligatorweed
Alternanthera philoxeroides
Plant(s)
James H. Miller
2117095
2117095

alligatorweed
Alternanthera philoxeroides
Foliage
Chris Evans
2131098
2131098

alligatorweed
Alternanthera philoxeroides
Plant(s)
Chris Evans
5376307
5376307

alligatorweed
Alternanthera philoxeroides
Fruit(s)
Julia Scher
2117081
2117081

alligatorweed
Alternanthera philoxeroides
Infestation
Chris Evans
2117087
2117087

alligatorweed
Alternanthera philoxeroides
Infestation
Chris Evans
5306061
5306061

alligatorweed
Alternanthera philoxeroides
Plant(s)
USDA PLANTS Database

Maps


EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

EDDMapS Distribution

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org

State Regulated List

Most Troublesome / Most Common Agricultural Weed List
This map identifies those states that consider this species either most troublesome or most common in at least one commodity. For more information, visit the MTMC project page.

State Regulated List
Legend
   No Data for this state
   Troublesome or Common weed in one or more crops

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Caryophyllidae
Order: Caryophyllales
Family: Amaranthaceae
Genus: Alternanthera

Other System Links

Plants: ALPH
Bayer: ALRPH
GRIN: 101502
ITIS: 20770
NPDN Pest: PAFABBA
NPDN Host: 31794

Synonyms and Other Names

Other Common Names:
alligator weed, pig weed

Related Scientific Names:

Achyranthes philoxeroides (Mart.) Griseb.(Synonym)

Categories

Category: Aquatic
Category: Forbs/Herbs